Coagulation is a critical process that allows damaged parts of the body to be maintained. When damage occurs to skin tissue or other body tissue in the form of a cut, the blood begins to clot. A blood clot, or blood clotting, is part of a process called hemostasis, and during this process, bleeding stops because the blood vessels constrict and a platelet plug forms. Blood clotting is essential for the repair and maintenance of the body, and without it, a cut would continue to bleed, causing hemorrhage. An abnormal blood clot condition called thrombosis arises when blood cells produce blood clots that travel through the bloodstream and clog blood vessels.
If body tissue is damaged by a cut or other injury, chemical signals called chemoattractants activate thrombocytes, also called platelets. Platelets are a type of white blood cell, and when activated, they disperse proteins within the body that work to seal off damaged tissue. These white blood cells float freely in the bloodstream and act quickly and efficiently to clot blood after injury.
Thrombocytes release the proteins thrombin and fibrinogen when activated by chemical signals after injury. Thrombin works to disrupt fibrinogen which causes fibrin production. Fibrin is a substance that causes blood to clot and is widely released from thrombocytes rapidly after injury. It is released in connective layers that begin to form around the outside of the cut, eventually moving inward and forming a blood clot. When the damaged region is sealed off, white blood cells called leukocytes move into the area to prevent any contamination that may occur from bacteria or viruses.
When blood clots normally, it will usually form a gap in a vessel; However, this does not happen in all cases. A condition called thrombosis arises when blood does not clot properly. Abnormal fibrin coagulation can lead to masses that break away from a blood clot and move freely through the bloodstream. The floating blood clot is called a thrombus.
A thrombus can cause blockage of arteries, capillaries, and veins, which are vessels that are important in supplying blood to certain organs in the body. The blockage occurs when the thrombus eventually moves through a vessel that becomes smaller in diameter. Once the vessel is blocked, oxygen, blood, and nutrients that are vital to the body will not be able to pass through, making thrombosis a serious medical condition.